TC7109/A
DS21456D-page 22 2002-2012 Microchip Technology Inc.
5.0 INTEGRATING CONVERTER
FEATURES
The output of integrating ADCs represents the integral,
or average, of an input voltage over a fixed period of
time. Compared with techniques in which the input is
sampled and held, the integrating converter averages
the effects of noise. A second important characteristic
is that time is used to quantize the answer, resulting in
extremely small non-linearity errors and no missing
output codes. The integrating converter also has very
good rejection of frequencies whose periods are an
integral multiple of the measurement period. This
feature can be used to advantage in reducing line
frequency noise (Figure ).
FIGURE 5-1: Normal Mode Rejection of
Dual Slope Converter as a Function of
Frequency
30
20
10
0
0.1/t 1/t 10/t
Input Frequency
Normal Mode Rejection Plan
t = Measurement
Period
